scholarly journals General mitigation techniques for coherent beam instabilities in particle accelerators

2021 ◽  
Vol 137 (1) ◽  
Author(s):  
Elias Métral
Keyword(s):  
High Energy ◽  
Coherent Beam ◽  
Particle Accelerator ◽  
Mitigation Measures ◽  
Particle Accelerators ◽  
Machine Performance ◽  
Beam Lifetime ◽  
Dynamic Aperture ◽  
Mitigation Methods ◽  
Beam Instabilities

AbstractAn important number of coherent beam instability mechanisms can be observed in a particle accelerator, depending if the latter is linear or circular, operated at low, medium or high energy, with a small or a huge amount of turns (for circular machines), close to transition energy or not (below or above), with only one bunch or many bunches, with counter-rotating beams (such as in colliders) or not, if the beam is positively or negatively charged, if one is interested in the longitudinal plane or in the transverse plane, in the presence of linear coupling between the transverse planes or not, in the presence of nonlinearities or not, in the presence of noise or not, etc. Building a realistic impedance model of a machine is a necessary step to be able to evaluate the machine performance limitations, identify the main contributors in case an impedance reduction is required, and study the interaction with other mechanisms such as optics (linear and nonlinear), RF gymnastics, transverse damper, noise, space charge, electron cloud, and beam–beam (in a collider). Better characterising an instability is the first step before trying to find appropriate mitigation measures and push the performance of a particle accelerator, as some mitigation methods are beneficial for some effects and detrimental for some others. For this, an excellent instrumentation is of paramount importance to be able to diagnose if the instability is longitudinal or transverse, single bunch, or coupled bunch, involving only one mode of oscillation or several, and the evolution of the intrabunch motion with intensity is a fundamental observable with high-intensity high-brightness beams. Finally, among the possible mitigation methods of coherent beam instabilities, the ones perturbing the least the single-particle motion (leading to the largest necessary dynamic aperture and beam lifetime) and easiest to implement for day-to-day operation in the machine control room should be preferred.

scholarly journals Safety Engineering for the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory

1999 ◽  
Author(s):  
Stephen V. Musolino ◽  
Steven F. Kane ◽  
Joseph W. Levesque
Keyword(s):  
Heavy Ion ◽  
High Energy ◽  
Particle Accelerator ◽  
Cryogenic System ◽  
High Energy Particle ◽  
Particle Accelerators ◽  
Safety Engineering ◽  
Relativistic Heavy Ion Collider ◽  
Energy Particle ◽  
Experimental Apparatus

Abstract The Relativistic Heavy Ion Collider (RHIC) is a high energy particle accelerator built to study basic nuclear physics. It consists of two counter-rotating beams of fully stripped gold ions that are accelerated in two rings to an energy of 100 GeV/nucleon. The rings consist of a circular lattice of superconducting magnets, 3.8 km in circumference. The beams can be stored for a period of five to ten hours and brought into collision for experiments during that time. The first major physics objective when the facility goes into operation is to recreate a state of matter, the quark-gluon plasma, that has been predicted to have existed at a short time after the creation of the universe. There are only a few other high energy particle accelerators like RHIC in the world. Each one is unique in design and contains systems and hazards that are not commonly found in general industry. Therefore, the designers of the machine do not always have consensus design standards and regulatory guidance available to establish the engineering parameters for safety. Some of the areas where standards are not available relate to the cryogenic system, containment of large volumes of flammable gas in fragile vessels in the experimental apparatus and mitigation of a Design Basis Accident with a stored particle beam. The ASME Code requires Charpy testing of welds at cryogenic temperature, but testing at 4 K is nearly impossible to conduct. Engineered welds were used to provide an equivalent level of safety. A cryogenic system is a process system. The RHIC system was designed first by selecting a safe operating mode, then analyzing to ensure this mode was preserved. Cryogenic systems have unique processes, and the safe mode will surprise most process engineers. The experimentalists require detectors to be designed to meet the need of the physics objectives, but the application of standard construction techniques would make research mission impossible. Unique but equivalent safety engineering must be determined. The rules promulgated in the Code of Federal Regulations under the Atomic Energy Act do not cover prompt radiation from accelerators, nor are there any State regulations that govern the design and operation of a large superconducting collider. Special design criteria for prompt radiation were developed to provide guidance for the design of radiation shielding.

scholarly journals Superconducting Materials and Conductors: Fabrication and Limiting Parameters

2012 ◽  
Vol 05 ◽  
pp. 25-50 ◽  
Author(s):  
Luca Bottura ◽  
Arno Godeke
Keyword(s):  
High Temperature Superconductors ◽  
High Energy ◽  
Particle Accelerator ◽  
Superconducting Materials ◽  
High Energy Particle ◽  
Particle Accelerators ◽  
Energy Particle ◽  
The Past ◽  
Accelerator Magnets ◽  
Limiting Parameters

Superconductivity is the technology that enabled the construction of the most recent generation of high-energy particle accelerators, the largest scientific instruments ever built. In this review we trace the evolution of superconducting materials for particle accelerator magnets, from the first steps in the late 1960s, through the rise and glory of Nb–Ti in the 1970s, till the 2010s, and the promises of Nb3Sn for the 2020s. We conclude with a perspective on the opportunities for high-temperature superconductors (HTSs). Many such reviews have been written in the past, as witnessed by the long list of references provided. In this review we put particular emphasis on the practical aspects of wire and tape manufacturing, cabling, engineering performance, and potential for use in accelerator magnets, while leaving in the background matters such as the physics of superconductivity and fundamental material issues.

scholarly journals Development and characterization of Nb3Sn/Al2O3 superconducting multilayers for particle accelerators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chris Sundahl ◽  
Junki Makita ◽  
Paul B. Welander ◽  
Yi-Feng Su ◽  
Fumitake Kametani ◽  
...  
Keyword(s):  
High Performance ◽  
High Energy ◽  
Particle Accelerators ◽  
Quality Factors ◽  
Critical Fields ◽  
Linear Accelerators ◽  
Cross Sectional ◽  
Low Field ◽  
Superconducting Radio Frequency

AbstractSuperconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 1010 at 1–2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200–240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb3Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration field in Nb3Sn, it has been proposed to coat Nb cavities with thin film Nb3Sn multilayers with dielectric interlayers. Here, we report the growth and multi-technique characterization of stoichiometric Nb3Sn/Al2O3 multilayers with good superconducting and RF properties. We developed an adsorption-controlled growth process by co-sputtering Nb and Sn at high temperatures with a high overpressure of Sn. The cross-sectional scanning electron transmission microscope images show no interdiffusion between Al2O3 and Nb3Sn. Low-field RF measurements suggest that our multilayers have quality factor comparable with cavity-grade Nb at 4.2 K. These results provide a materials platform for the development and optimization of high-performance SIS multilayers which could overcome the intrinsic limits of the Nb cavity technology.

Particle accelerators in Mexico

2006 ◽  
Vol 36 (2) ◽  
pp. 297-309
Author(s):  
MARÍÍA DE LA PAZ RAMOS LARA
Keyword(s):  
Latin America ◽  
Nuclear Physics ◽  
Particle Accelerator ◽  
Particle Accelerators ◽  
Van De Graaff ◽  
Experimental Nuclear Physics

ABSTRACT The first Van de Graaff particle accelerator in Latin America was installed at the Universidad Nacional Autóónoma de Mééxico (UNAM) in 1952. This event marked the beginning of experimental nuclear physics, exclusively for peaceful purposes, in Mexico. The acquisition of this accelerator was fundamental for placing other accelerators into operation, which were used for both research and the resolution of national problems.

Medical Cyclotrons

2009 ◽  
Vol 02 (01) ◽  
pp. 133-156 ◽  
Author(s):  
D. L. Friesel ◽  
T. A. Antaya
Keyword(s):  
Cancer Therapy ◽  
Scientific Research ◽  
High Energy ◽  
Industrial Applications ◽  
Medical Applications ◽  
Particle Accelerators ◽  
Radioisotope Production ◽  
Practical Applications ◽  
Medical Radioisotope ◽  
High Energy Particles

Particle accelerators were initially developed to address specific scientific research goals, yet they were used for practical applications, particularly medical applications, within a few years of their invention. The cyclotron's potential for producing beams for cancer therapy and medical radioisotope production was realized with the early Lawrence cyclotrons and has continued with their more technically advanced successors — synchrocyclotrons, sector-focused cyclotrons and superconducting cyclotrons. While a variety of other accelerator technologies were developed to achieve today's high energy particles, this article will chronicle the development of one type of accelerator — the cyclotron, and its medical applications. These medical and industrial applications eventually led to the commercial manufacture of both small and large cyclotrons and facilities specifically designed for applications other than scientific research.

AMBEMAR-DSS: A Decision Support System for the Environmental Impact Assessment of Marine Renewable Energies

2018 ◽  
Author(s):  
Xabier Guinda ◽  
Araceli Puente ◽  
José A. Juanes ◽  
Francisco Royano ◽  
Felipe Fernández ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Impact Assessment ◽  
Environmental Impact Assessment ◽  
Energy Demand ◽  
High Energy ◽  
Renewable Energies ◽  
Environmental Cost ◽  
Assessment Process ◽  
Mitigation Measures ◽  
Modeling Tools

The high energy demand and the threat of climate change have led to a remarkable development of renewable energies, initially through technologies applied to the terrestrial environment and, recently, through the awakening of marine renewable energies. However, the development of these types of projects is often hampered by failure to pass the corresponding environmental impact assessment process. The complexity of working in the marine environment and the uncertainties associated with assessing the impacts of such projects make it difficult to carry out objective and precise environmental impact assessments. AMBEMAR-DSS seeks to establish a basis for understanding and agreement between the different stakeholders (project developers, public administrations, environmental organizations and the public in general), in order to find solutions that allow the development of marine renewable energies, minimizing their environmental cost. For this purpose, a DSS is proposed which, based on cartographic information and using objective and quantifiable criteria, allows comparative assessments and analyses between different project alternatives. The analytical procedures used by the system include, among others, hydrodynamic modeling tools and visual impact simulators. In addition, impacts on marine species are assessed taking into account intrinsic ecological and biological aspects. The magnitude of the impacts is quantified by means of fuzzy logic operations and the integration of all the elements is carried out by an interactive multi-criteria analysis. The results are shown in tables, graphs and figures of easy interpretation and can be also visualized geographically by means of a cartographic viewer. The system identifies the main impacts generated in the different phases of the project and allows establishing adequate mitigation measures in search of optimized solutions. The establishment of the assessment criteria has been based on the abundant, but dispersed, scientific literature on the various elements of the system and having the opinion of experts in the various fields. Nevertheless, the DSS developed constitutes a preliminary basis on which to build and improve a system with the input of researchers, promoters and experts from different disciplines.

scholarly journals The starburst galaxy NGC 253 revisited by H.E.S.S. and Fermi-LAT

2018 ◽  
Vol 617 ◽  
pp. A73 ◽  
Author(s):  
◽  
H. Abdalla ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
E. O. Angüner ◽  
...  
Keyword(s):  
Spectral Index ◽  
Power Law ◽  
Cosmic Ray ◽  
High Energy ◽  
Thick Target ◽  
Starburst Galaxy ◽  
Particle Accelerators ◽  
Power Law Distribution ◽  
Particle Population ◽  
Measurement Uncertainties

Context. NGC 253 is one of only two starburst galaxies found to emit γ-rays from hundreds of MeV to multi-TeV energies. Accurate measurements of the very-high-energy (VHE; E > 100 GeV) and high-energy (HE; E > 60 MeV) spectra are crucial to study the underlying particle accelerators, probe the dominant emission mechanism(s) and to study cosmic-ray interaction and transport. Aims. The measurement of the VHE γ-ray emission of NGC 253 published in 2012 by H.E.S.S. was limited by large systematic uncertainties. Here, the most up to date measurement of the γ-ray spectrum of NGC 253 is investigated in both HE and VHE γ-rays. Assuming a hadronic origin of the γ-ray emission, the measurement uncertainties are propagated into the interpretation of the accelerated particle population. Methods. The data of H.E.S.S. observations are reanalysed using an updated calibration and analysis chain. The improved Fermi–LAT analysis employs more than 8 yr of data processed using pass 8. The cosmic-ray particle population is evaluated from the combined HE–VHE γ-ray spectrum using NAIMA in the optically thin case. Results. The VHE γ-ray energy spectrum is best fit by a power-law distribution with a flux normalisation of (1.34 ± 0.14stat ± 0.27sys) × 10−13 cm−2 s−1 TeV1 at 1 TeV – about 40% above, but compatible with the value obtained in Abramowski et al. (2012). The spectral index Γ = 2.39 ± 0.14stat ± 0.25sys is slightly softer than but consistent with the previous measurement within systematic errors. In the Fermi energy range an integral flux of F(E > 60 MeV) = (1.56 ± 0.28stat ± 0.15sys) × 10−8 cm−2 s−1 is obtained. At energies above ∼3 GeV the HE spectrum is consistent with a power-law ranging into the VHE part of the spectrum measured by H.E.S.S. with an overall spectral index Γ = 2.22 ± 0.06stat. Conclusions. Two scenarios for the starburst nucleus are tested, in which the gas in the starburst nucleus acts as either a thin or a thick target for hadronic cosmic rays accelerated by the individual sources in the nucleus. In these two models, the level to which NGC 253 acts as a calorimeter is estimated to a range of fcal = 0.1 to 1 while accounting for the measurement uncertainties. The presented spectrum is likely to remain the most accurate measurements until the Cherenkov Telescope Array (CTA) has collected a substantial set of data towards NGC 253.

scholarly journals Ionization Dosimetry Principles for Conventional and Laser-Driven Clinical Particle Beams

2018 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Ionizing Radiation ◽  
Heavy Particle ◽  
Absorbed Dose ◽  
High Energy ◽  
Particle Energy ◽  
Particle Accelerators ◽  
Carbon Ions ◽  
Particle Beams ◽  
Radiation Fields ◽  
Number Of Particles

In this paper after mentioning the clinical radiation fields of 20 keV-450 MeV/u, they are characterized by the number of particles and their energy. Particle energy is the quantity that determines radiation penetration at the depth at which the tumor is situated (Fig. 1). The number of particles (or beam intensity) is the second major quantity that assures the administration of the absorbed dose in the tumor. The first application shows the radiation levels planned for various radiation fields. Prior to interacting with the medium, the intensity (or energy fluence rate) allows the determination of energy density, energy, power and relativistic force. In the interaction process, it determines the absorbed dose, kerma and exposure. Non-ionizing radiations in the EM spectrum are used as negative energy waves to accelerate particles charged into special installations called particle accelerators. The particles extracted from the accelerator are the source of the corpuscular radiation for high-energy radiotherapy. Of these, light particle beams (electrons and photons) for radiotherapy are generated by betatron, linac, microtron, and synchrotron and heavy particle beams (protons and heavy ions) are generated by cyclotron, isochronous cyclotron, synchro-cyclotron and synchrotron. The ionization dosimetry method used is the ionization chamber for both indirectly ionizing radiation (photons and neutrons) and for directly ionizing radiation (electrons, protons and carbon ions). Because the necessary energies for hadrons therapy are relatively high, 50-250 MeV for protons and 100-450 MeV/u for carbon ions, the alternative to replace non-ionizing radiation with relativistic laser radiation for generating clinical corpuscular radiation through radiation pressure acceleration mechanism (RPA) is presented.

scholarly journals Application of Radiation-Thermal Treatment to Suppress Sensitivity of Silicon Microcircuits to Single Radiation Effects

2021 ◽  
Vol 8 (3) ◽  
pp. 99-103
Author(s):  
P. B. Lagov ◽  
◽  
A. S. Drenin ◽  
A. A. Meshcheryakov ◽  
N. A. Yudanov ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Integrated Circuits ◽  
Radiation Effects ◽  
Experimental Tests ◽  
High Energy ◽  
Particle Accelerators ◽  
Transfer Coefficients ◽  
Heavy Charged Particles ◽  
Equilibrium Charge ◽  
Technological Tool

The paper analyses the possibility to reduce the sensitivity of silicon integrated circuits (ICs) to single radiation effects by means of radiation-thermal treatment including irradiation in charged particle accelerators and subsequent low-temperature heat treatment. It is shown that reduction in sensitivity to single radiation effects is provided by formation of thermostable recombination centers in semiconductor IC structure in necessary concentrations. At the same time a decrease in primary photocurrent generated by heavy charged particles or high-energy protons, reduction in transfer coefficients of parasitic bipolar transistors forming thyristor structures, reduction in carrier avalanche multiplication coefficients at high electric field strengths can be provided. Radiationthermal treatment can be introduced in the manufacturing process of ICs of various classes at the end of the manufacturing cycle and does not require correction of the basic technology. A possible undesirable growth of inverse currents and preservation of values of other electrical parameters within acceptable values when using radiation-thermal treatment is provided by choosing optimal modes of irradiation and annealing which are established in the course of experimental tests. The calculated evaluation has shown that using radiation-thermal treatment in the technology of IC fabrication can provide a decrease in the effective collection length of non-equilibrium charge carriers generated under the influence of single radiation effects by at least 10 times which allows considering radiation-thermal treatment as an effective technological tool to suppress the sensitivity to single radiation effects.

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